Genetics

<span style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-weight: 700; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;">Genetics is a branch of <a href="https://en.wikipedia.org/wiki/Biology" title="Biology" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">biology</a> concerned with the study of <a href="https://en.wikipedia.org/wiki/Gene" title="Gene" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">genes</a>, <a href="https://en.wikipedia.org/wiki/Genetic_variation" title="Genetic variation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">genetic variation</a>, and <a href="https://en.wikipedia.org/wiki/Heredity" title="Heredity" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">heredity</a> in <a href="https://en.wikipedia.org/wiki/Organism" title="Organism" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline; color: rgb(107, 75, 161);">organisms</a>.<div><p style="margin: 0.5em 0px 1em; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;">Though heredity had been observed for millennia, <a href="https://en.wikipedia.org/wiki/Gregor_Mendel" title="Gregor Mendel" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">Gregor Mendel</a>, a scientist and <a href="https://en.wikipedia.org/wiki/Augustinian" title="Augustinian" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">Augustinian</a> <a href="https://en.wikipedia.org/wiki/Friar" title="Friar" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">friar</a> working in the 19th century, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene.<p style="margin: 0.5em 0px 1em; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;"><a href="https://en.wikipedia.org/wiki/Phenotypic_trait" title="Phenotypic trait" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">Trait</a> inheritance and <a href="https://en.wikipedia.org/wiki/Molecular_genetics" title="Molecular genetics" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">molecular</a> inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded beyond inheritance to studying the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the <a href="https://en.wikipedia.org/wiki/Cell(biology)" title="Cell (biology)" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">cell</a>, the organism (e.g. <a href="https://en.wikipedia.org/wiki/Dominance(genetics)" title="Dominance (genetics)" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">dominance</a>), and within the context of a population. Genetics has given rise to a number of subfields, including <a href="https://en.wikipedia.org/wiki/Epigenetics" title="Epigenetics" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">epigenetics</a> and <a href="https://en.wikipedia.org/wiki/Population_genetics" title="Population genetics" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">population genetics</a>. Organisms studied within the broad field span the domains of life (<a href="https://en.wikipedia.org/wiki/Archaea" title="Archaea" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">archaea</a>, <a href="https://en.wikipedia.org/wiki/Bacteria" title="Bacteria" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">bacteria</a>, and <a href="https://en.wikipedia.org/wiki/Eukarya" title="Eukarya" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">eukarya</a>).<p style="margin: 0.5em 0px 1em; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Lato, Helvetica, Arial, sans-serif; vertical-align: baseline;">Genetic processes work in combination with an organism's environment and experiences to influence development and <a href="https://en.wikipedia.org/wiki/Behavioural_genetics" title="Behavioural genetics" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">behavior</a>, often referred to as <a href="https://en.wikipedia.org/wiki/Nature_versus_nurture" title="Nature versus nurture" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">nature versus nurture</a>. The <a href="https://en.wikipedia.org/wiki/Intracellular" title="Intracellular" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">intracellular</a> or <a href="https://en.wikipedia.org/wiki/Extracellular" title="Extracellular" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">extracellular</a> environment of a cell or organism may switch gene transcription on or off. A classic example is two seeds of genetically identical corn, one placed in a temperate climate and one in an arid climate. While the average height of the two corn stalks may be genetically determined to be equal, the one in the <a href="https://en.wikipedia.org/wiki/Arid_climate" title="Arid climate" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font: inherit; vertical-align: baseline; color: rgb(107, 75, 161);">arid climate</a> only grows to half the height of the one in the temperate climate due to lack of water and nutrients in its environment.</div>